1. Field of the Invention
This invention relates to an improvement for an attenuator to clamp vibrations and noise occurring when remachining or resurfacing a disc brake rotor by a pair of cutter bits in a machining tool or lathe.
2. Background Information
The faces of disc brake rotors become worn and damaged after long periods use. They must be machined to provide a smooth surface to improve braking. The machining of the disc brake rotors is done by placing them in a lathe machine where they are clamped in place and then machining opposite sides simultaneously with cutter bits as the brake rotor is rotated in the machine. Previously this machining technique caused a great deal of vibration and noise from the metal-on-metal affect of the cutting bits engaging the surfaces of the rotor. The noise produced by this machining is not only unpleasant for the machining tool operator and others in the area, but also can produce vibrations that adversely affect the machining.
For this reason, an attenuator disclosed and described in U.S. Pat. Nos. 4,531,434 and 6,227,085 of Vasquez issued Jul. 30, 1985 and May 8, 2001, respectively, was conceived to dampen and attenuate the noise and vibrations caused during the machining process. The vibration attenuator of these patents is comprised of a pad assembly including a pair of pads adapted to rest in frictional engagement against opposite faces of the disc brake rotor. They also rest on the tips of the cutter bits with biasing means urging the pads against the rotor faces. The pads are pressed against the faces of the rotor whereby rotation of the rotor in the brake lathe forcibly urges the pads against the lathe cutter bits. This close association of the attenuator with the pads and the cutter bits acts to attenuate vibration as well as that of the rotor. Each pad on the attenuator carries an element which projects into engagement with cutter bits. Movement of the cutter bits in a cutting direction causes the pad elements to be carried by the bits in turn movement of the pad in common with the cutter bits. Preferably the vibration attenuator the pads are pivotable through 180° to allow a fresh wearing surface to be applied to the cutter bits and the surfaces of the rotor.
Other systems employed to damp such vibrations include pads designed to bear against opposite faces of the rotor out of the way of the cutter bits. The pads are carried by a complex mounting structure secured to the brake lathe. Precise arrangement or adjustment of the position of the pads is required and elaborate linkage arrangement is provided to accompany the adjustment. This adjustment is relatively complex and costly.
Another system utilizes a resilient band adapted to be stretched and placed upon the circumference of the rotor. A set of such bands must be purchased to accommodate the various sizes of rotors to be machined. This system is unsatisfactory because attenuation is inadequate and the additional bands to accommodate various size of roller to be machined must be purchased.
It is therefore one object of the present invention to provide an improved attenuator for disc brake rotor, a machining tools or lathe.
Yet another object of the present invention is to provide an improved attenuator for disc brake rotor machining tools having biasing arms angled downward at approximately 45° toward the machining tool cutting bits to increase stability.
Yet another object of the present invention is to provide an improved attenuator machining tool having silencing pads with notch cut out of the pads to allow them to fit around and rest on top of cutter bits regardless of the adjustment of the cutter arms.
Still another object of the present invention is to provide an attenuator for attenuating the vibration and noise of cutter bits when machining a disc brake rotor in which a handle with a pair of legs biases damping pads against the surface of the disc brake rotor in which the legs of the handle extend from a squared end and toward each other so they subtend an angle relative to the squared end that is greater than 90°.
Yet another object of the present invention is to provide a strap that is attached to the straight portion on the squared end of the handle that allows the tool to be conveniently fastened to the carriage of the machining tool or lathe.